On the basis of an automated transmission (hereafter referred to as AMT) in which the transmission operation of a manual transmission having high transmission efficiency is automated and for the purpose of preventing shocks due to torque interruption during transmission shifting, a hybrid vehicle drive unit (AMT-HEV) equipped with a twin-clutch type transmission, the two input shafts of which have gear groups and can be connected to an engine via clutches respectively and one input shaft of which can be driven by a motor generator, has been proposed conventionally (refer to Patent document 1).
In the vehicle drive unit 100 described in Patent document 1, as shown in FIG. 28, two input shafts 101 and 102 are connected to an engine Eng through clutches C1 and C2 respectively, and a motor generator MG is connected to the input shaft 102. Furthermore, when the input shaft 102 is connected to a counter shaft 107 through a low-speed gear train 106 by engaging a dog clutch 105, and the input shaft 101 is connected to the counter shaft 107 through a high-speed gear train 109 by engaging a dog clutch 108.
In addition, it is disclosed that when shift-up is performed depending on vehicle speed during low-speed traveling after the dog clutch 105 is engaged and the clutch C2 is engaged, the engagement of the dog clutch 108 is started, the clutch C2 is released, and the clutch C1 is engaged. Hence, shift-up from the low-speed side to the high-speed side is performed.